JPH11157356A - Four-wheel drive system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of vibration when a two-way clutch is locked or freed by detecting the oil temperature at the time of the low- temperature start of a vehicle to reduce the idle revolving speed of the two-way clutch, or reduce the viscosity of oil. SOLUTION: When a driver selects a mode selecting switch 23 to a two-WD mode for a travel at the time of the low-temperature start of a vehicle, the signal of the oil temperature measured value in a transfer 5 by a temperature sensor 32 is inputted to an ECU 33. If the oil temperature measured value is lower than the prescribed temperature set in the ECU 33 in advance, a hub clutch 2 or a front wheel axle engaging/disengaging means is engaged. The rotation of front wheels 1 is transferred to an outer ring 13, the outer ring 13 is rotated in the same direction as an inner member 12, the idle revolving speed of the inner member 12 and the outer ring 13 is reduced, and the occurrence of a lock of a two-way clutch 10 due to oil drag resistance can be prevented even when the viscosity of a lubricant 31 is increased at a low temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-wheel drive control system for a 4WD vehicle provided with a rotation transmission device for switching between transmission and interruption of a driving force on a driving path of the vehicle. The present invention relates to a system capable of maintaining functions at the time of starting.

[0002]

2. Description of the Related Art When a 4WD vehicle having directly connected front and rear wheels turns on a paved road, a so-called tight corner braking phenomenon occurs. As a means for solving this problem, the present applicant has filed Japanese Patent Application No. 8-172598. And Japanese Patent Application No. 9-28001
Has proposed a rotation transmission device using a roller type two-way clutch and current control means.

[0003] As shown in FIGS. 5 and 6, this rotation transmitting device A is provided in a FR-based 4WD vehicle in which a hub clutch 2 is mounted at each end of a front wheel 1 in a transmission 4 connected to an engine 3. The output is transmitted directly to the propulsion shaft 8 of the rear wheel 7 via the input shaft 6 inside the transfer 5, and inside the transfer 5, the input shaft 6 and a chain sprocket 9 mounted coaxially with the input shaft 6 so as to be relatively rotatable.
Mechanism 22 for synchronizing and rotating input shaft 6
A two-way clutch 10 using a roller as an engaging element for transmitting and blocking the rotation of the sprocket 9 and the input shaft 6, and an electromagnetic control means for controlling locking and free of the two-way clutch 10 A clutch 11 is provided, which allows a conventional typical part-time 4WD
Traveling mode of (2WD, 4WD-Hi, 4WD -L 0)
In addition, a control mode of 4WD is added.

FIG. 7 shows a specific structure of the two-way clutch 10 and the electromagnetic clutch 11 in the rotation transmitting device A.
The two-way clutch 10 rotatably fits the inner member 12 and the outer ring 13 coaxially via a bearing, and
A plurality of cam surfaces 14 are provided on one of the outer ring 13 and the other, a cylindrical surface 15 is provided on the other, a wedge-shaped space is formed between both surfaces, a retainer 16 is provided in the wedge-shaped space, and the cage 16 is formed. A roller 17 as an engaging element is incorporated in a plurality of pockets, and a switch spring 18 for supporting and urging the retainer 16 to a neutral position where the roller 17 does not engage the cylindrical surface 15 and the cam surface 14 is provided. And is locked between the inner member 12 or the outer ring 13 having

The electromagnetic clutch 11 is a current control means for controlling the lock and free of the two-way clutch 10.
Is formed by laminating a friction flange 19 fixed to the outer ring 13 or the inner member 12 and an armature 20 fitted to the end of the cage 16 so as to be slidable with the cage 16 so as not to rotate relative thereto, through an appropriate gap. In addition, an electromagnetic coil 21 for bringing the friction flange 19 and the armature 20 into pressure contact with each other by a magnetic force is provided, and the roller 17 is engaged or idled by turning on and off the current of the electromagnetic coil 21.

[0006] By the way, the 4WD vehicle exerts its power in a low-temperature snowfall area, but when the vehicle is started at a low temperature, the oil filled in the transfer is also low in temperature and its viscosity is large.

[0007] The above 4WD vehicle has a mode changeover switch 2
When the vehicle travels with the 2WD mode or AUTO mode selected by 3, the hub clutch 2 is turned off, the front drive system stops rotating, and the two-way clutch 10 enters the idle state.

[0008]

As described above, when the vehicle is started at a low temperature, the oil in the transfer is also low in temperature and high in viscosity, so that the two-way clutch 1 is selected when the 2WD mode is selected.
When the value of 0 is idling in which the inner member 12 rotates with respect to the stop of the outer ring 13, the roller 17 may be locked due to drag resistance of the oil.

After locking, the relative rotation between the outer race 13 and the inner member 12 of the two-way clutch 10 is stopped, and the lock is released again without being affected by the oil.

That is, the two-way clutch 10 repeatedly locks and frees, which causes a problem that vibration is generated.

An object of the present invention is to reduce the idling speed of the two-way clutch or reduce the viscosity of the oil by detecting the oil temperature when the vehicle is started at a low temperature, and to lock and free the two-way clutch. An object of the present invention is to provide a drive system for a 4WD vehicle equipped with a rotation transmission device capable of preventing generation of vibration.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention according to claim 1 transmits an output from a transmission directly to a rear-wheel propulsion shaft via an internal input shaft, and further comprises: A rotation transmission device for switching between 2WD and 4WD is mounted inside a FR-based transfer for a 4WD vehicle that can branch power to the propulsion shaft, and the rotation transmission device
A two-way clutch using an engagement element, and current control means for controlling lock and free of the two-way clutch;
The present invention employs a configuration in which the current control means and the hub clutch or the axle coupling / disengaging device are controlled depending on a signal of a temperature sensor for detecting the oil temperature of the lubricating oil in the transfer.

According to a second aspect of the present invention, a hub clutch or an axle coupling and disengaging device for switching between coupling and disengagement between the front wheel propulsion shaft and the front wheel is incorporated between the front wheel propulsion shaft and the front wheel.

According to a third aspect of the present invention, a configuration is adopted in which a signal from the temperature sensor is input to the controller, and the controller controls the current to the current control means in accordance with the content of the signal.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

A first embodiment of the system shown in FIGS. 1 to 3 is a transfer system in which a rotation transmitting device A is housed.
A temperature sensor 32 for detecting the oil temperature of the lubricating oil 31 housed therein.

An oil temperature detection signal from the temperature sensor 32 is input to an ECU (controller) 33,
Numeral 3 is for operating the actuator of the hub clutch 2.

At the time of starting the vehicle at low temperature, when the driver travels with the mode changeover switch 23 selected to the 2WD mode, a signal of the measured oil temperature in the transfer 5 by the temperature sensor 32 is input to the ECU 33, If the measured value is lower than the preset temperature set in the ECU 33, the hub clutch 2 or the front wheel axle disengaging means is engaged.

When the 2WD mode is selected, in the conventional rotation transmitting device A, the inner member 12 idles with respect to the outer ring 13 to be stopped. At this time, the hub clutch 2 or the front wheel axle engaging / disengaging means is engaged. In this case, the rotation of the front wheel 1 is transmitted to the outer wheel 13, and the outer wheel 13 rotates in the same direction as the inner member 12, whereby the number of idle rotations of the inner member 12 and the outer wheel 13 decreases, and the lubricating oil 31 is removed. Even if the viscosity is high at low temperatures, 2
Locking of the way clutch 10 can be prevented.

When the oil temperature in the transfer 5 rises as the vehicle travels and the oil temperature measured by the temperature sensor 32 exceeds the set temperature, the hub clutch 2 or the front axle engagement / disengagement means is disengaged, and the front wheels are driven. Stop the system and normal 2W
Set to D mode.

When the oil temperature of the lubricating oil 31 in the transfer 5 rises above a set value, the viscosity of the oil decreases and the drag resistance decreases. Therefore, the front wheel drive system is stopped and the outer wheel 13 and the inner member 12 are stopped. Even if relative rotation occurs,
The way clutch 10 does not engage, and therefore, it is possible to effectively prevent the two-way clutch 10 from repeatedly locking and freeing and generating vibrations at the time of low temperature starting.

Next, in the system according to the second embodiment shown in FIG. 4, the rotation transmitting device A is mounted on the front wheel output shaft 34 in the lower part of the transfer 5, and the synchronizing mechanism 22, the two-way clutch 10 and the electromagnetic clutch 11 Are arranged so as to be immersed in the lubricating oil 31, and a temperature sensor 32 for detecting the oil temperature of the internal lubricating oil 31 is attached to the transfer 5.

In the second embodiment, at the time of starting the vehicle at a low temperature, when the driver selects the mode changeover switch 23 to the 2WD mode and travels, the temperature sensor 3
The signal of the oil temperature measurement value in the transfer 5 due to the
When the oil temperature is input to U33 and the measured oil temperature is lower than the preset temperature preset in the ECU 33, as shown in FIG.
Electromagnetic coil 21 serving as current control means of electromagnetic clutch 11
And / or energize the electromagnetic coil 24 of the synchronizing mechanism 22 to instantaneously raise the oil temperature of the lubricating oil 31 in the transfer 5, especially the temperature in the two-way clutch 10, by the heat generated by the electromagnetic coils 21 and 24. This reduces the viscosity of the lubricating oil 31 and prevents the two-way clutch 10 from locking due to drag resistance of the oil 31.

In the second embodiment, the voltage when the electromagnetic coil 21 is energized when the AUTO mode is selected depends on the friction flange 1 generated when the electromagnetic coil 21 is energized.
The frictional force between the armature 9 and the armature 20 is set to a value that does not exceed the torque of the switch spring 18 so that the two-way clutch 10 is not locked.

In each of the above embodiments, the control of the hub clutch 2 and the electromagnetic coils 21 and 24 by the oil temperature measurement signal of the temperature sensor 32 is performed by setting the set temperature I and the set temperature II in the ECU 33, With hysteresis,
When the set temperature II is set higher than the set temperature I and the measured temperature of the temperature sensor 32 is equal to or lower than the set temperature I, the engagement of the hub clutch 2 or the energization of the electromagnetic coils 21 and 24 is performed. If it exceeds II, the hub clutch 2 is disengaged or the electromagnetic coils 21 and 24 are turned off.

In the first embodiment, the engagement and disengagement of the hub clutch 2 is performed.
Although the energization to 4 is turned on and off independently, both embodiments may be used in combination.

[0027]

As described above, according to the present invention, the oil temperature in the transfer is detected and the 2WD or AU
When the vehicle travels in the TO mode, the front wheel drive system is rotated, so that the number of idle rotations of the two-way clutch in the rotation transmission device can be reduced. Locking of the way clutch can be prevented, and vibration due to repetition of lock and free of the two-way clutch can be prevented.

When the vehicle is driven in the 2WD or AUTO mode at a low temperature start, if the current control means of the rotation transmitting device is energized, the heat generated by the current control means raises the oil temperature of the lubricating oil and increases its viscosity. Can be made smaller,
Locking of the two-way clutch due to drag resistance of the oil can be prevented.

[Brief description of the drawings]

FIG. 1 shows a 4WD showing a first embodiment of a control system.
Plan view showing layout of driving car

FIG. 2 is a block diagram of a control system.

FIG. 3 is a flowchart showing the operation of the control system.

FIG. 4 is a plan view showing a layout of a 4WD drive vehicle in which a rotation transmission device is mounted on a lower output shaft.

FIG. 5 is a plan view showing a layout of a 4WD drive vehicle incorporating a rotation transmission device.

FIG. 6 is a cross-sectional view of a transfer incorporating a rotation transmitting device.

7A is a longitudinal sectional view of a rotation transmitting device, and FIG. 7B is a longitudinal sectional view of the same.

[Explanation of symbols]

 5 Transfer 6 Input shaft 10 2 Way clutch 11 Electromagnetic clutch 12 Inner member 14 Cam surface 15 Cylindrical surface 16 Cage 17 Roller 18 Switch spring 21 Electromagnetic coil 22 Synchro mechanism 23 Mode switch 31 Lubricating oil 32 Temperature sensor 33 ECU

Claims (3)

[Claims] An output from a transmission is directly transmitted to a rear wheel propulsion shaft via an internal input shaft, and power is branched to a front wheel propulsion shaft. A rotation transmission device for switching the 4WD is mounted, and the rotation transmission device uses an engagement element.
A current control means for controlling locking and freeing of the two-way clutch; and a signal from a temperature sensor for detecting the oil temperature of lubricating oil in the transfer. A four-wheel drive system characterized in that control is performed in accordance with the following. 2. The four-wheel drive system according to claim 1, further comprising a hub clutch or an axle connection / disengagement device for switching between connection and release between the front wheel propulsion shaft and the front wheel, between the front wheel propulsion shaft and the front wheel. 3. The four-wheel drive system according to claim 1, wherein a signal from the temperature sensor is input to the controller, and the controller controls the current to the current control means according to the content of the signal.